1. Field of the Invention
The present invention relates to a drawing apparatus for inserting and drawing out an electrical machinery of a drawer type, which is accommodated in switch gear.
2. Discussion of Background
FIG. 8 is a perspective view illustrating a conventional drawing apparatus disclosed in, for example, Japanese Unexamined Utility Model Publication JP-A-48-43931. In FIG. 8, numerical reference 1 designates a breaker; numerical reference 2 designates a screw rod, penetrating through a dolly of the breaker 1 so as to be rotatable; numerical reference 3 designates a nut located on a side of a switch gear; and numerical reference 4 designates a handle, engaged with the screw rod 2, for rotating the screw rod 2.
When the breaker is inserted in the switch gear, the screw rod is made in contact with the nut 3, and the handle 4 is turned to rotate the screw rod 2, whereby the screw rod 2 is screwed into the nut 3. Because the nut 3 is fixed to the switch gear (not shown), the breaker is drawn into the switch gear along with the rotation of the screw rod 2. By rotating the screw rod 2 in a direction adverse to described above, the nut 3 is moved relatively left in FIG. 8, whereby the breaker 1 is drawn out of the switch gear.
However, the conventional apparatus has a problem that various types of screw rods, corresponding to various sizes of breakers, are necessary because a length of the screw rod is determined by an overall depth of the breaker or a distance between a breaking position and a making position of the switch gear. Further, there is a problem that a large space should be prepared in a manufacturing factory, and at time of installing and transporting.
It is an object of the present invention to solve the above-mentioned problems inherent in the conventional technique and to provide a drawing apparatus which can deal with breakers having any size without changing components of the drawing apparatus.
Another object of the present invention is to provide a drawing apparatus which can be easily installed inside switch gear.
Another object of the present invention is to provide a drawing apparatus, which can be safely operated by detecting making and breaking states of a switch.
Another object of the present invention is to provide a means for detecting making and breaking states, which can securely detect the making and breaking states of a switch in a simple structure.
Another object of the present invention is to provide a shutter which can easily realize an operation interlocked with a means for detecting making and breaking states.
Another object of the present invention is to provide a drawing apparatus which can be easily assembled.
According to a first aspect of the present invention, there is provided a drawing apparatus comprising: a screw rod rotatably supported around an axis center along a direction of drawing an electrical machinery; and a nut engaged with the electrical machinery, screwed with the screw rod, and driving the electrical machinery in a direction of inserting or drawing out by moving the electrical machinery of a drawing type in directions of inserting and drawing out upon the rotation of the screw rod.
According to a second aspect of the present invention, there is provided a drawing apparatus comprising: a screw rod supported by a floor of an electrical machinery room so as to be rotatable around an axis center along a direction of drawing out the electrical machinery; and a nut engaging a lower portion of the electrical machinery in directions of inserting and drawing out, screwed with the screw rod, and driving the electrical machinery in the directions of inserting and drawing out the electrical machinery by moving the electrical machinery upon the rotation of the screw rod.
According to a third aspect of the present invention, there is provided a drawing apparatus comprising: a screw rod rotatably supported around an axis center along a drawing direction of a switch; a nut engaged with the switch, screwed with the screw rod, and driving the switch in directions of inserting and drawing out the switch by moving the switch in the directions; a making and breaking state detecting means detecting making and breaking states of the switch; and a shutter closing a front surface of a driving portion of the screw rod, engaged with the making and breaking state detecting means on one side thereof, and being movable in a position of releasing the front surface of the driving portion of the screw rod only in case that the making and breaking state detecting means detects the breaking state.
According to a fourth aspect of the present invention, there is provided the drawing apparatus, wherein the making and breaking state detecting means comprising: an interlocking member installed in the switch and moving between making and breaking positions of the switch; and an interlocking rod having a shaft rotatably supported in parallel with the screw rod, an arm-like detector, rotated along with the shaft, engaged with the interlocking member, and detecting the making and breaking states of the switch, and an arm-like actuator located in one end of the shaft and outputting a detected state.
According to a fifth aspect of the present invention, there is provided the drawing apparatus, wherein the shutter is located on a front surface of a driving portion of the screw rod so as to be freely slidable in directions perpendicular to a longitudinal direction of the screw rod, and the shutter is rotated in a direction that the interlocking rod is in contact with the interlocking member of the switch by an engagement between one side of the shutter and a roller, located in a tip of a displaying portion of the interlocking rod of the making and breaking state detecting means in case that the shutter slides in a direction of releasing the front surface of the driving portion.
According to a sixth aspect of the present invention, there is provided the drawing apparatus, wherein the screw rod, the making and breaking state detecting means, and the shutter are constructed to be a single unit on a common base.